CN110911277A - Etching method - Google Patents
Etching method Download PDFInfo
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- CN110911277A CN110911277A CN201811080846.5A CN201811080846A CN110911277A CN 110911277 A CN110911277 A CN 110911277A CN 201811080846 A CN201811080846 A CN 201811080846A CN 110911277 A CN110911277 A CN 110911277A
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- 238000000034 method Methods 0.000 title claims abstract description 129
- 238000005530 etching Methods 0.000 title claims abstract description 91
- 230000003197 catalytic effect Effects 0.000 claims abstract description 115
- 230000008569 process Effects 0.000 claims abstract description 96
- 239000012265 solid product Substances 0.000 claims abstract description 24
- 239000007789 gas Substances 0.000 claims description 185
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 124
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 55
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 33
- 229910000040 hydrogen fluoride Inorganic materials 0.000 claims description 33
- 238000010926 purge Methods 0.000 claims description 19
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 10
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 239000011261 inert gas Substances 0.000 claims description 3
- 229910021529 ammonia Inorganic materials 0.000 claims description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 52
- 239000000377 silicon dioxide Substances 0.000 description 26
- 235000012239 silicon dioxide Nutrition 0.000 description 25
- 238000000137 annealing Methods 0.000 description 7
- 230000009471 action Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000000126 substance Substances 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 230000005669 field effect Effects 0.000 description 3
- 238000002955 isolation Methods 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 229910019975 (NH4)2SiF6 Inorganic materials 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000009022 nonlinear effect Effects 0.000 description 1
- LXPCOISGJFXEJE-UHFFFAOYSA-N oxifentorex Chemical compound C=1C=CC=CC=1C[N+](C)([O-])C(C)CC1=CC=CC=C1 LXPCOISGJFXEJE-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66787—Unipolar field-effect transistors with an insulated gate, i.e. MISFET with a gate at the side of the channel
- H01L29/66795—Unipolar field-effect transistors with an insulated gate, i.e. MISFET with a gate at the side of the channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Ceramic Engineering (AREA)
- Drying Of Semiconductors (AREA)
Abstract
The invention provides an etching method, which comprises the following steps: introducing a first catalytic gas, a second catalytic gas and a process gas into the reaction chamber, so that the first catalytic gas and the second catalytic gas both participate in the reaction to etch the workpiece to be processed; and removing solid products formed on the workpiece to be processed. The etching method provided by the invention can reduce the difference of etching amount and the generation of bowl-shaped phenomenon and groove-shaped phenomenon after etching, and can reduce the process time and improve the process efficiency and the productivity.
Description
Technical Field
The invention relates to the technical field of semiconductor manufacturing processes, in particular to an etching method.
Background
In recent years, with the increase of the integration level of integrated circuits, the size of transistors is getting smaller, and the multi-dimensional and non-linear effects such as short channel effect, leakage induced barrier effect, hot carrier effect, etc. are getting more and more prominent. Therefore, fin field effect transistors (finfets) having better channel control capability, and thus faster switching speed and higher current density, are attracting attention as compared to planar Metal Oxide Semiconductor Field Effect Transistors (MOSFETs).
As shown in fig. 1-4, a critical step in the finfet device fabrication process is Shallow Trench Isolation (STI) etching. The Fin (Fin)1 exposed to a certain height is formed after etching, the height of the Fin 1 can influence the grid control voltage, and therefore the exposed heights of all the fins 1 after etching are required to be consistent, however, it is difficult to ensure that the exposed heights of the fins 1 after etching are completely consistent in an actual process, difference (loading) of etching amount is easy to occur, and as shown in the figure, some unreacted silicon dioxide (silicon oxide)2 can be remained at the side wall of the Fin 1 after etching to form a bowl shape (footing), or as shown in the figure, some silicon dioxide 2 can be over-etched to form a trench shape (trench), and the performance of the device can be seriously influenced by the phenomena. Therefore, it is very important to develop a process for efficiently reducing the bowl-type phenomenon and the trench-type phenomenon after shallow trench isolation etching in the fin field effect transistor.
In the current shallow trench isolation etching process, Hydrogen Fluoride (HF) gas phase etching is the mainstream, but the hydrogen fluoride gas phase etching rate is relatively slow, and a catalytic gas is usually introduced to accelerate the reaction. However, in the etching process using a mixture of hydrogen fluoride and methanol, the density and the like are sensitive to the doping condition of silicon dioxide 2, the etching rate of the N-Well (N-Well) doped with phosphorus (P) or arsenic (As) is slow, and the etching effect is good, but the etching rate of the P-Well (P-Well) doped with boron (B) is fast, so that As shown in fig. 1 and 3, the etching amount in the fin 1 is higher than that outside the fin 1, a difference (positive loading) in the positive etching amount is formed, and a bowl-shaped phenomenon is easily generated.
In the etching process of mixing hydrogen fluoride and ammonia gas, a solid product is formed, the density of the solid product is insensitive to the doping condition of silicon dioxide 2, but after the thickness of the solid product reaches a certain degree, the etching rate is saturated, the etching cannot be continued, the solid product needs to be sublimated at high temperature, after the solid product is sublimated, the etching amount in the fin 1 is lower than the etching amount outside the fin 1, a negative etching amount difference (negative loading) is formed, and after the thickness of the solid product reaches a certain degree, the solid product needs to be sublimated at high temperature firstly and then subjected to etching reaction, so that the process time is increased, and the process efficiency and the productivity are reduced. In addition, since the amount of solid products formed on the sidewall of the fin 1 is small, the etching rate is fast, and the trench-type phenomenon as shown in fig. 4 is easily formed.
Disclosure of Invention
The invention aims to at least solve one of the technical problems in the prior art, and provides an etching method which can reduce the difference of etching amount and the generation of bowl-shaped phenomenon and groove-shaped phenomenon after etching, can reduce the process time, and can improve the process efficiency and the productivity.
To achieve the object of the present invention, there is provided an etching method comprising:
introducing a first catalytic gas, a second catalytic gas and a process gas into the reaction chamber, so that the first catalytic gas and the second catalytic gas both participate in the reaction to etch the workpiece to be processed; and
and removing solid products formed on the workpiece to be processed.
Preferably, the step of introducing the first catalytic gas, the second catalytic gas and the process gas into the reaction chamber further comprises:
simultaneously introducing the first catalytic gas and the second catalytic gas into the reaction chamber;
and introducing the process gas into the reaction chamber after waiting for the first preset time.
Preferably, the step of introducing the first catalytic gas, the second catalytic gas and the process gas into the reaction chamber further comprises:
introducing one of the first catalytic gas and the second catalytic gas into the reaction chamber;
after waiting for a second preset time, simultaneously introducing the process gas and the other catalytic gas into the reaction chamber; or after waiting for a second preset time, introducing another catalytic gas or the process gas into the reaction chamber, and after waiting for a third preset time, introducing the process gas or the another catalytic gas into the reaction chamber.
Preferably, the first catalytic gas is an alcohol gas; the second catalytic gas is ammonia gas; the process gas is hydrogen fluoride.
Preferably, before the step of removing the solid product formed on the workpiece to be processed, the method further comprises:
introducing a purging gas into the reaction chamber for purging; and introducing ammonia gas into the reaction chamber while introducing purge gas into the reaction chamber.
Preferably, the purge gas comprises nitrogen or an inert gas.
Preferably, the first catalytic gas is methanol, and the flow ratio of methanol to ammonia in the etching process is in a value range of 4:1-100: 1.
preferably, the flow rate of the methanol is 50sccm to 2000 sccm.
Preferably, the flow rate of the ammonia gas ranges from 2sccm to 500 sccm.
Preferably, the flow rate of the hydrogen fluoride ranges from 10sccm to 500 sccm; the process pressure is in the range of 1Torr-200 Torr; the temperature of the workpiece to be processed ranges from 10 ℃ to 90 ℃.
The invention has the following beneficial effects:
according to the etching method provided by the invention, the first catalytic gas, the second catalytic gas and the process gas are introduced into the reaction chamber, so that the first catalytic gas and the second catalytic gas both participate in the reaction to etch the workpiece to be processed, and a solid product formed on the workpiece to be processed is removed after etching to obtain the required workpiece to be processed.
Drawings
FIG. 1 is a schematic diagram illustrating a difference in positive etching amount after a wafer is etched in the prior art;
FIG. 2 is a schematic diagram illustrating a difference in negative etching amount after a wafer is etched according to the prior art;
FIG. 3 is a schematic diagram illustrating a bowl-shaped phenomenon after a wafer is etched in the prior art;
FIG. 4 is a diagram illustrating a trench type phenomenon occurring after a wafer is etched in the prior art;
FIG. 5 is a flow chart of a first specific process of the etching method provided by the present invention;
FIG. 6 is a flow chart of a second specific process of the etching method provided by the present invention;
FIG. 7 is a flow chart of a third embodiment of the etching method according to the present invention;
FIG. 8 is a flow chart of a fourth specific process of the etching method according to the present invention;
FIG. 9 is a flow chart of a fifth specific process of the etching method according to the present invention;
FIG. 10 is a flow chart of a sixth specific process of the etching method according to the present invention;
FIG. 11 is a schematic view of a sequence of introducing gases in the etching method according to the present invention;
FIG. 12 is a schematic view showing another sequence of introducing gases in the etching method according to the present invention;
FIG. 13 is a schematic diagram of a wafer after etching the wafer by the etching method of the present invention.
Description of reference numerals:
1-a fin; 2-silicon dioxide; 31-methanol; 32-ammonia gas; 33-hydrogen fluoride; 34-purge gas.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the following describes the etching method provided by the present invention in detail with reference to the accompanying drawings.
As shown in fig. 5to 12, in the present embodiment, the etching method includes the following steps:
s1, introducing a first catalytic gas, a second catalytic gas and a process gas into the reaction chamber;
and S2, removing solid products formed on the workpiece to be processed.
The first catalytic gas and the second catalytic gas are reacted, the first catalytic gas and the second catalytic gas are etched together with the process gas on the workpiece to be processed, and the first catalytic gas and the second catalytic gas compensate each other by means of the combined action of the first catalytic gas and the second catalytic gas, so that the etching depths of all parts of the workpiece to be processed tend to be consistent.
As shown in fig. 1to 4 and fig. 12, taking the first catalytic gas as methanol 31, the second catalytic gas as ammonia gas 32, the process gas as hydrogen fluoride 33, and the etched object on the workpiece to be processed as silicon dioxide 2 as an example, it is specifically described how the combined action of the first catalytic gas and the second catalytic gas makes the etching depth regions of the workpiece to be processed uniform, but the first catalytic gas, the second catalytic gas, the process gas, and the etched object on the workpiece to be processed are not limited thereto, and other alcohol gases may be used as the first catalytic gas.
In practical applications, after etching the silicon dioxide 2 on the workpiece to be processed, a plurality of sets of fins 1 are formed on the workpiece to be processed, each set of fins 1 includes a plurality of fins 1, an area between adjacent fins 1 in each set is referred to as an inner fin 1, and an area between the plurality of sets of fins 1 is referred to as an outer fin 1.
After etching the silicon dioxide 2 using the methanol 31 alone as the catalytic gas and the hydrogen fluoride 33, a difference is formed in which the height of the silicon dioxide 2 inside the fin 1 is higher than the height of the silicon dioxide 2 outside the fin 1 as shown in fig. 1, that is, the etching depth inside the fin 1 is smaller than the etching depth outside the fin 1, which is called a positive etching amount, and a bowl-type phenomenon is also formed in which the edge area of the silicon dioxide 2 is higher than the center area as shown in fig. 3.
After etching the silicon dioxide 2 using the ammonia gas 32 alone as the catalytic gas and the hydrogen fluoride 33, a difference is formed in which the height of the silicon dioxide 2 inside the fin 1 is lower than the height of the silicon dioxide 2 outside the fin 1 as shown in fig. 2, that is, the etching depth inside the fin 1 is greater than the etching depth outside the fin 1, which is called a negative etching amount, and a trench-type phenomenon is also formed in which the center region of the silicon dioxide 2 is higher than the edge region as shown in fig. 4.
Compared with the single use of the methanol 31 as the catalytic gas and the single use of the ammonia gas 32 as the catalytic gas, two diametrically opposite etching results are formed after the silicon dioxide 2 on the workpiece to be processed is etched, so that through the combined action of the methanol 31 and the ammonia gas 32, the etching of the ammonia gas 32 and the hydrogen fluoride 33 on the silicon dioxide 2 can compensate the defects caused by the etching of the ammonia gas 32 and the hydrogen fluoride 33 on the silicon dioxide 2, and the etching of the ammonia gas 32 and the hydrogen fluoride 33 on the silicon dioxide 2 can also compensate the defects caused by the etching of the methanol 31 and the hydrogen fluoride 33 on the silicon dioxide 2, so that the etching depths of the workpiece to be processed at different positions tend to be consistent through the combined action of the methanol 31 and the ammonia gas 32.
In addition, when the ammonia gas 32 and the hydrogen fluoride 33 etch the silicon dioxide 2, a solid substance of ammonium hexafluorosilicate ((NH4)2SiF6) is formed and deposited on the silicon dioxide 2, and in order to obtain a desired work, it is necessary to remove the solid substance.
According to the etching method provided by the embodiment, the first catalytic gas, the second catalytic gas and the process gas are introduced into the reaction chamber, so that the first catalytic gas and the second catalytic gas both participate in the reaction to etch the workpiece to be processed, and a solid product formed on the workpiece to be processed is removed after etching, so that the required workpiece to be processed is obtained.
As shown in fig. 6, optionally, step S1 further includes:
s111, simultaneously introducing a first catalytic gas and a second catalytic gas into the reaction chamber;
and S112, introducing process gas into the reaction chamber after waiting for the first preset time.
Specifically, a first catalytic gas and a second catalytic gas are simultaneously introduced into a reaction chamber, so that the first catalytic gas and the second catalytic gas are adsorbed on the surface of the workpiece to be processed in advance, and then introduced into the reaction chamber for a first preset time, and then introduced into the reaction chamber to react with the workpiece to be processed under the combined action of the process gas and the first catalytic gas and the second catalytic gas adsorbed on the surface of the workpiece to be processed in advance, so that the first catalytic gas and the second catalytic gas both participate in the reaction.
As shown in fig. 10, taking the first catalytic gas as methanol 31, the second catalytic gas as ammonia gas 32, the process gas as hydrogen fluoride 33, and the etched object on the workpiece to be processed as silicon dioxide 2 as an example for specific description, firstly, methanol 31 and ammonia gas 32 are introduced into the reaction chamber, and after 5s-200s of methanol 31 and ammonia gas 32 are introduced, hydrogen fluoride 33 is introduced into the reaction chamber for 1s-150s while methanol 31 and ammonia gas 32 are continuously introduced. The first preset time is 5s-200s, the methanol 31 and the ammonia gas 32 need to be matched properly, the flow ratio of the methanol 31 to the ammonia gas 32 is 4:1-100:1, the flow ratio of the methanol 31 is 50sccm-2000sccm, 100sccm is usually used, the flow ratio of the ammonia gas 32 is 2sccm-500sccm, 50sccm is usually used, and the flow ratio of the hydrogen fluoride 33 is 10sccm-500 sccm.
It should be noted that, when the hydrogen fluoride 33 and the ammonia gas 32 are introduced into the reaction chamber, since the hydrogen fluoride 33 and the ammonia gas 32 neutralize each other, the hydrogen fluoride 33 and the ammonia gas 32 may not be mixed in advance before entering the reaction chamber, i.e. the hydrogen fluoride 33 and the ammonia gas 32 need to be introduced into the reaction chamber through different gas inlet pipes.
It should be noted that the time for introducing the gas may be changed according to the etching depth of the workpiece to be processed and the difference of the gas introduced into the reaction chamber. In addition, when the process gas is simultaneously in the reaction chamber with the first catalytic gas and the second catalytic gas, the workpiece to be processed begins to be etched.
As shown in fig. 7, optionally, step S1 further includes:
s121, introducing one of a first catalytic gas and a second catalytic gas into the reaction chamber;
s122, after waiting for a second preset time, simultaneously introducing a process gas and another catalytic gas into the reaction chamber; or after waiting for a second preset time, introducing another catalytic gas or process gas into the reaction chamber; and introducing the process gas or another catalytic gas into the reaction chamber after waiting for the third preset time.
Specifically, the first catalytic gas may be introduced into the reaction chamber, and after waiting for a second predetermined time, the process gas and the second catalytic gas may be introduced into the reaction chamber at the same time; or after waiting for a second preset time, introducing a second catalytic gas into the reaction chamber, and after waiting for a third preset time, introducing a process gas into the reaction chamber: or after waiting for the second preset time, introducing process gas into the reaction chamber, and after waiting for the third preset time, introducing a second catalytic gas into the reaction chamber.
Or introducing a second catalytic gas into the reaction chamber, and introducing the process gas and the first catalytic gas into the reaction chamber simultaneously after waiting for a second preset time; or after waiting for the second preset time, introducing a first catalytic gas into the reaction chamber, and after waiting for the third preset time, introducing a process gas into the reaction chamber: or after waiting for the second preset time, introducing process gas into the reaction chamber, and after waiting for the third preset time, introducing the first catalytic gas into the reaction chamber.
As shown in fig. 11, taking the first catalytic gas as methanol 31, the second catalytic gas as ammonia gas 32, the process gas as hydrogen fluoride 33, and the etched object on the workpiece to be processed as silicon dioxide 2 as an example for specific description, firstly introducing methanol 31 into the reaction chamber, introducing ammonia gas 32 into the reaction chamber while continuing to introduce methanol 31 after introducing methanol 31 for 5s-60s, introducing hydrogen fluoride 33 into the reaction chamber for 1s-150s while continuing to introduce methanol 31 and ammonia gas 32 after introducing ammonia gas 32 for 5s-60s, wherein the value ranges of the second predetermined time and the third predetermined time are 5s-60s, the methanol 31 and ammonia gas 32 need to be properly proportioned, the normal ratio range of the flow rates of the methanol 31 and ammonia gas 32 is 4:1-100:1, the value range of the flow rate of the methanol 31 is 50sccm-2000sccm, the flow rate of the ammonia gas 32 is usually 100sccm, the flow rate of the hydrogen fluoride 33 is usually 50sccm, and the flow rate of the ammonia gas is usually 10sccm to 500 sccm.
It should be noted that the time for introducing the gas may be changed according to the etching depth of the workpiece to be processed and the difference of the gas introduced into the reaction chamber.
As shown in fig. 8, in the present embodiment, after step S2, the method further includes:
s3, judging whether the etching depth of the workpiece to be processed reaches the preset etching depth; if yes, go to step S4 to end the process; if not, the process returns to step S1.
It should be noted that, in the process of etching the workpiece to be processed, a solid product is formed on the surface of the workpiece to be processed, and the number of the solid products on the surface of the workpiece to be processed increases, so that when the solid product is accumulated to a certain thickness, the etching rate is saturated, that is, the workpiece to be processed cannot be etched, and at this time, the solid substance needs to be removed, so that the workpiece to be processed can be etched continuously.
In this embodiment, the etching rate of the workpiece to be processed can be increased by the combined action of the first catalytic gas and the second catalytic gas, and compared with the prior art, when the solid products are accumulated to the same thickness, the workpiece to be processed can be etched more deeply, so that the cycle number of the process is reduced, the process time is further reduced, and the process efficiency and the productivity are improved.
Optionally, in step S2, the reaction chamber is heated, and the workpiece to be processed is subjected to an annealing process to remove the solid product.
Optionally, in step S2, the workpiece to be processed is moved into the annealing chamber, and the annealing process is performed on the workpiece to be processed to remove the solid products.
It should be noted that the temperature of the etching process ranges from 10 ℃ to 90 ℃, and the solid product can be removed only by high-temperature sublimation, so the temperature of the annealing process ranges from 120 ℃ or more. In addition, in practical application, before moving the workpiece to be processed out of the reaction chamber, the reaction chamber needs to be vacuumized, then the workpiece to be processed is transferred to the annealing chamber, the annealing chamber is heated, so that a solid product is sublimated, then the workpiece to be processed needs to be cooled, then the workpiece to be processed is transferred to the reaction chamber to be etched continuously, and the process can be completed within 5-10 min.
As shown in fig. 9, in the present embodiment, before step S2, the method further includes:
and S13, introducing the purge gas 34 into the reaction chamber for purging, and purging the process gas remained in the reaction chamber and on the surface of the workpiece to be processed. The residual process gas is prevented from being diffused to the outside when the reaction chamber is opened, and the residual process gas on the surface of the workpiece to be processed is prevented from influencing the process effect of the workpiece to be processed in the subsequent annealing process or other processes.
As shown in fig. 10, optionally, step S13 further includes:
s131, introducing the ammonia gas 32 into the reaction chamber while introducing the purge gas 34 into the reaction chamber for purging, and purging the process gas together with the purge gas 34, so that the residual process gas is purged more cleanly.
Specifically, the example that the first catalytic gas is methanol 31, the second catalytic gas is ammonia gas 32, the process gas is hydrogen fluoride 33, and the etched object on the workpiece to be processed is silicon dioxide 2 is specifically described, wherein the ammonia gas 32 is alkaline, the hydrogen fluoride 33 is acidic, and the ammonia gas 32 and the hydrogen fluoride 33 can be neutralized by acid and alkali, so that the residue of the process gas is reduced.
In the present embodiment, the purge gas 34 comprises nitrogen or an inert gas, preferably high Purity Nitrogen (PN)2)。
Preferably, high purity nitrogen gas can be used as the purge gas 34, and the flow rate of the purge gas 34 can range from 1000sccm to 3000 sccm.
In the present embodiment, the first catalytic gas is methanol 31, but the first catalytic gas is not limited thereto, and for example, an alcohol gas such as ethanol or isopropyl alcohol may be used.
In this example, the second catalytic gas is ammonia gas 32.
In the present embodiment, the process gas is hydrogen fluoride 33.
In this embodiment, the first catalytic gas is methanol, the second catalytic gas is ammonia gas, and the ratio of methanol to ammonia gas in the etching process has a value range of 4:1-100: 1.
in this embodiment, the first catalytic gas is methanol, the second catalytic gas is ammonia gas, the time for introducing the methanol into the reaction chamber ranges from 5s to 200s, and the flow rate of the methanol ranges from 50sccm to 2000 sccm.
In this embodiment, the first catalytic gas is methanol, the second catalytic gas is ammonia gas, the time for introducing ammonia gas into the reaction chamber ranges from 5s to 200s, and the flow rate of ammonia gas ranges from 2sccm to 500 sccm.
In this embodiment, the time period for introducing the process gas into the reaction chamber ranges from 1s to 150s, and the flow rate of the process gas ranges from 10sccm to 500 sccm.
In this embodiment, the process gas is hydrogen fluoride 33, and the flow rate of the hydrogen fluoride 33 ranges from 10sccm to 500 sccm; the process pressure is in the range of 1Torr-200 Torr; the temperature of the workpiece to be processed ranges from 10 ℃ to 90 ℃.
Specifically, a first catalytic gas is methanol 31, a second catalytic gas is ammonia gas 32, a process gas is hydrogen fluoride 33, an etched object on a workpiece to be processed is silicon dioxide 2, and the first catalytic gas is prepared by setting a plurality of different process parameter ratios, wherein the flow rate of the methanol 31 is 2000sccm, the flow rate of the ammonia gas 32 is 500sccm, the process temperature is 20 ℃, the process pressure is 10Torr, and the process time is 60 s; secondly, the flow rate of the methanol 31 is 50sccm, the flow rate of the ammonia gas 32 is 2sccm, the process temperature is 10 ℃, the process pressure is 20Torr, and the process time is 140 s; thirdly, the flow rate of the methanol 31 is 1000sccm, the flow rate of the ammonia gas 32 is 50sccm, the process temperature is 40 ℃, the process pressure is 5Torr, and the process time is 100s, wherein the ratio of the flow rates of the methanol 31 and the ammonia gas 32 ranges from 4: 1to 100: 1.
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.
Claims (10)
1. An etching method, comprising:
introducing a first catalytic gas, a second catalytic gas and a process gas into the reaction chamber, so that the first catalytic gas and the second catalytic gas both participate in the reaction to etch the workpiece to be processed; and
and removing solid products formed on the workpiece to be processed.
2. The etching method of claim 1, wherein the step of introducing a first catalytic gas, a second catalytic gas and a process gas into the reaction chamber further comprises:
simultaneously introducing the first catalytic gas and the second catalytic gas into the reaction chamber;
and introducing the process gas into the reaction chamber after waiting for the first preset time.
3. The etching method of claim 1, wherein the step of introducing a first catalytic gas, a second catalytic gas and a process gas into the reaction chamber further comprises:
introducing one of the first catalytic gas and the second catalytic gas into the reaction chamber;
after waiting for a second preset time, simultaneously introducing the process gas and the other catalytic gas into the reaction chamber; or after waiting for a second preset time, introducing another catalytic gas or the process gas into the reaction chamber, and after waiting for a third preset time, introducing the process gas or the another catalytic gas into the reaction chamber.
4. The etching method according to any one of claims 1to 3, wherein the first catalytic gas is an alcohol gas; the second catalytic gas is ammonia gas; the process gas is hydrogen fluoride.
5. The etching method according to claim 4, further comprising, before the step of removing solid products formed on the workpiece to be processed:
introducing a purging gas into the reaction chamber for purging; and introducing ammonia gas into the reaction chamber while introducing purge gas into the reaction chamber.
6. The etching method according to claim 5, wherein the purge gas comprises nitrogen or an inert gas.
7. The etching method according to claim 4, wherein the first catalytic gas is methanol, and the flow ratio of methanol to ammonia in the etching process is in a range of 4:1-100: 1.
8. the etching method according to claim 7, wherein the flow rate of methanol is in a range of 50sccm to 2000 sccm.
9. The etching method according to claim 8, wherein the flow rate of the ammonia gas is in a range of 2sccm to 500 sccm.
10. The etching method according to claim 9, wherein the flow rate of hydrogen fluoride has a value in a range of 10sccm to 500 sccm; the process pressure is in the range of 1Torr-200 Torr; the temperature of the workpiece to be processed ranges from 10 ℃ to 90 ℃.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112530780A (en) * | 2020-11-27 | 2021-03-19 | 北京北方华创微电子装备有限公司 | Semiconductor etching method |
| CN112530780B (en) * | 2020-11-27 | 2024-05-17 | 北京北方华创微电子装备有限公司 | Semiconductor etching method |
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| CN101440498A (en) * | 2007-11-19 | 2009-05-27 | 中芯国际集成电路制造(上海)有限公司 | Method for precleaning thin film surface oxide before deposition |
| KR20110123084A (en) * | 2010-05-06 | 2011-11-14 | 주식회사 테스 | Dry etch method for silicon oxide |
| CN107464749A (en) * | 2017-07-28 | 2017-12-12 | 北京北方华创微电子装备有限公司 | Engraving method and etch system |
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| KR20110123084A (en) * | 2010-05-06 | 2011-11-14 | 주식회사 테스 | Dry etch method for silicon oxide |
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